And while Japan has approved the joint agreement, Foreign Minister Taro Aso was quoted as saying that Tokyo would not provide aid as there had been no progress on the issue of Japanese nationals abducted by the North in the 1970s and 80s.

But despite the difficulties ahead, analysts say this deal is an important sign of progress, after more than three years of talks.

The previous deal, agreed in September 2005, rapidly fell apart over differences between North Korea and the US over implementation.

The North Korean nuclear issue has become even more pressing in recent months, after Pyongyang conducted its first atomic test in October.